Efthalia Chatzisymeon

The environmental footprint of a membrane bioreactor treatment process through Life Cycle Analysis

This study includes an environmental analysis of a membrane bioreactor (MBR), the objective being to quantitatively define the inventory of the resources consumed and estimate the emissions produced during its construction, operation and end-of-life deconstruction. The environmental analysis was done by the life cycle assessment (LCA) methodology, in order to establish with a broad perspective and in a rigorous and objective way the environmental footprint and the main environmental hotspots of the examined technology. Raw materials, equipment, transportation, energy use, as well as air- and waterborne emissions were quantified using as a functional unit, 1m(3) of urban wastewater. SimaPro 8.0.3.14 was used as the LCA analysis tool, and two impact assessment methods, i.e. IPCC 2013 version 1.00 and ReCiPe version 1.10, were employed. The main environmental hotspots of the MBR pilot unit were identified to be the following: (i) the energy demand, which is by far the most crucial parameter that affects the sustainability of the whole process, and (ii) the material of the membrane units. Overall, the MBR technology was found to be a sustainable solution for urban wastewater treatment, with the construction phase having a minimal environmental impact, compared to the operational phase. Moreover, several alternative scenarios and areas of potential improvement, such as the diversification of the electricity mix and the material of the membrane units, were examined, in order to minimize as much as possible the overall environmental footprint of this MBR system. It was shown that the energy mix can significantly affect the overall sustainability of the MBR pilot unit (i.e. up to 95% reduction of the total greenhouse gas emissions was achieved with the use of an environmentally friendly energy mix), and the contribution of the construction and operational phase to the overall environmental footprint of the system.

Environmental sustainability of the solar photo-Fenton process for wastewater treatment and pharmaceuticals mineralization at semi-industrial scale

The environmental sustainability of a semi-industrial solar photo-Fenton reactor, treating real effluents emanating from a pharmaceutical laboratory, is assessed herein. The life cycle assessment/analysis (LCA) methodology was employed and real life cycle inventory (LCI) data was collected from a ferrioxalate-assisted homogeneous solar photo-Fenton wastewater treatment plant (WWTP), at Ciudad Real, Spain. Electricity was provided by photovoltaic (PV) panels in tandem with a battery bank, making the plant autonomous from the local grid. The effective treatment of 1m3 of secondary-treated pharmaceutical wastewater, containing antipyrine, was used as a functional unit. The main environmental hotspot was identified to be the chemical reagents used to enhance treatment efficiency, mainly hydrogen peroxide (H2O2) and to a smaller degree oxalic acid. On the other hand, land use, PV panels, battery units, compound parabolic collectors (CPC), tanks, pipes and pumps, as materials, had a low contribution, ranging from as little as 0.06% up to about 2% on the total CO2eq emissions. Overall, the solar photo-Fenton process was found to be a sustainable technology for treating wastewater containing micropollutants at semi-industrial level, since the total environmental footprint was found to be 2.71kgCO2m-3 or 272mPtm-3, using IPCC 2013 and ReCiPe impact assessment methods, respectively. A sensitivity analysis revealed that if the excess of solar power is fed back into the grid then the total environmental footprint is reduced. Depending on the amount of solar power fed back into the grid the process could have a near zero total environmental footprint.

Solar Photocatalytic Degradation of Bisphenol A on Immobilized ZnO or TiO2

The removal of bisphenol A (BPA) under simulated solar irradiation and in the presence of either TiO2 or ZnO catalysts immobilized onto glass plates was investigated. The effect of various operating conditions on degradation was assessed including the amount of the immobilized catalyst (36.1–150.7u2009mg/cm2 for TiO2 and 0.5–6.8u2009mg/cm2 for ZnO), initial BPA concentration (50–200u2009μg/L), treatment time (up to 90u2009min), water matrix (wastewater, drinking water, and pure water), the addition of H2O2 (25–100u2009mg/L), and the presence of other endocrine disruptors in the reaction mixture. Specifically, it was observed that increasing the amount of immobilized catalyst increases BPA conversion and so does the addition of H2O2 up to 100u2009mg/L. Moreover, BPA degradation follows first-order reaction kinetics indicating that the final removal is not practically affected by the initial BPA concentration. Degradation in wastewater is slower than that in pure water up to five times, implying the scavenging behavior of effluent’s constituents against hydroxyl radicals. Finally, the presence of other endocrine disruptors, such as 17α-ethynylestradiol, spiked in the reaction mixture at low concentrations usually found in environmental samples (i.e., 100u2009μg/L), neither affects BPA degradation nor alters its kinetics to a considerable extent.

Life cycle assessment of the environmental performance of conventional and organic methods of open field pepper cultivation system

PurposeAs the scale of the organic cultivation sector keeps increasing, there is growing demand for reliable data on organic agriculture and its effect on the environment. Conventional agriculture uses chemical fertilizers and pesticides, whilst organic cultivation mainly relies on crop rotation and organic fertilizers. The aim of this work is to quantify and compare the environmental sustainability of typical conventional and organic pepper cultivation systems.MethodsTwo open field pepper cultivations, both located in the Anthemountas basin, Northern Greece, are selected as case studies. Life cycle assessment (LCA) is used to quantify the overall environmental footprint and identify particular environmental weaknesses (i.e. unsustainable practices) of each cultivation system. Results are analysed at both midpoint and endpoint levels in order to obtain a comprehensive overview of thexa0environmental sustainability of each system. Attributional LCA (ALCA) is employed to identify emissions associated with the life cycles of the two systems. Results are presented for problem-oriented (midpoint) and damage-oriented (endpoint) approaches, using ReCiPe impact assessment.Results and discussionAt midpoint level, conventional cultivation exhibits about threefold higher environmental impact on freshwater eutrophication, than organic cultivation. This arises from the extensive use of nitrogen and phosphorus-based fertilizers, with consequent direct emissions to the environment. The remaining impact categories are mainly affected by irrigation, with associated indirect emissions linked to electricity production. At endpoint level, the main hotspots identified for conventional cultivation are irrigation and fertilizing, due to intensive use of chemical fertilizers and (to a lesser degree) pesticides. For organic pepper cultivation, the main environmental hotspots are irrigation, machinery use, and manure loading and spreading processes. Of these, the highest score for irrigation derives from the heavy electricity consumption required for groundwater pumping associated with the fossil-fuel-dependent Greek electricity mix.ConclusionsOrganic and conventional cultivation systems have similar total environmental impacts per unit of product, with organic cultivation achieving lower environmental impacts in ‘freshwater eutrophication’, ‘climate change’, ‘terrestrial acidification’ and ‘marine eutrophication’ categories. Conventional cultivation has a significantly greater effect on the freshwater eutrophication impact category, due to phosphate emissions arising from application of chemical fertilizers.

Assessing the sustainability of acid mine drainage (AMD) treatment in South Africa

The environmental sustainability of acid mine drainage (AMD) treatment at semi-industrial scale is examined by means of the life cycle assessment (LCA) methodology. An integrated process which includes magnesite, lime, soda ash and CO2 bubbling treatment was employed to effectively treat, at semi-industrial scale, AMD originating from a coal mine in South Africa. Economic aspects are also discussed. AMD is a growing problem of emerging concern that cause detrimental effects to the environment and living organisms, including humans, and impose on development, health, access to clean water, thus also affect economic growth and cause social instability. Therefore, sustainable and cost effective treatment methods are required. A life cycle cost analysis (LCCA) revealed the viability of the system, since the levelized cost of AMD treatment can be as low as R112.78/m3 (€7.60/m3 or

Improving carbon coated TiO2 films with a TiCl4 treatment for photocatalytic water purification

9.35/m3). Moreover, due to its versatility, the system can be used both at remote locales, at stand-alone mode (e.g. using solar energy), or can treat AMD at industrial scale, thus substantially improving community resilience at local and national level. In terms of environmental sustainability, 29.6u202fkg CO2eq are emitted per treated m3 AMD or its environmental footprint amount to 2.96u202fPt/m3. South Africas fossil-fuel depended energy mix and liquid CO2 consumption were the main environmental hotspots. The total environmental footprint is reduced by 45% and 36% by using solar energy and gaseous CO2, respectively. Finally, AMD sludge valorisation, i.e. mineral recovery, can reduce the total environmental footprint by up to 12%.

Sequential ionic layer adsorption and reaction (SILAR) deposition of Bi4Ti3O12 on TiO2: an enhanced and stable photocatalytic system for water purification

By using a simple thermal decomposition route, carbon‐TiO2 hybrid films have been synthesized from a catechol‐TiO2 surface complex. The coated films display enhanced visible region absorption, owing to the thin (≈2u2005nm) layer of carbon encapsulating the TiO2. Although photocatalytically active under visible light alone, it is demonstrated that the activity of the carbon‐coated films can be improved further by a hydrolytic treatment with TiCl4, leading to the introduction of small TiO2 particles (5–10u2005nm) and doping of chlorine into the structure. The combination of the carbon layer and TiCl4 treatment gives increased photocatalytic performance for the photodegradation of dyes, phenolic pollutants and the reduction of toxic CrVI to relatively benign CrIII. In addition, the carbon‐coated films show improved bactericidal activity under UV irradiation, and hence have been successfully tested against the most common types of pollutant present in potential drinking waters.

Life cycle assessment of organic versus conventional agriculture. A case study of lettuce cultivation in Greece

A new method to produce bismuth titanate – titanium dioxide composites by modification of a TiO2 film deposited on a variety of different glass substrates is reported. Using a simple SILAR method, BiOBr may be deposited upon TiO2 surfaces, which upon heating forms a closely intercalated structure of bismuth titanate (Bi4Ti3O12, BTO) and TiO2. This new method expands the scope of the SILAR process, which is typically restricted to materials which can be formed from soluble precursors. This composite material has undergone a thorough materials characterisation to confirm the absence of the BiOBr precursor, and the formation of the new bismuth titanate phase. The electronic structure of the heterojunction formed has also been investigated by valence band XPS and diffuse reflectance measurements, and a plausible band structure proposed. The immobilised composites have then been applied to the photocatalytic degradation of organic pollutants and bactericidal testing, as well as stability tests and identification of the key reactive species. Further photocatalytic studies have been carried out on this material in a synthetic wastewater medium, taking a step towards application under real-world conditions.